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plotting sheet (see Section 7.8) the effect of inherent
errors is that, even for a target on a steady track, the
plotted positions do not form a perfectly straight line
but are scattered about the correct track; the observer
has to attempt to draw the line that is the best fit. Exactly
the same effect occurs with automatic plotting and it is
further exacerbated by quantizing errors introduced by
the digital storage (see Sections 2.6.6.1 and 9.5). Since
the data must eventually be displayed as a stable straight
line vector, the processor must calculate a length and
direction which represents the best fit to the